The present invention relates generally to a spool valve shifting mechanism and more particularly to an easily assembled, cam-operation, valve shifting mechanism.
In the past, cams were pinned or keyed into position on round shafts. This has the disadvantages of necessitating machining of pin holes or key ways into the shaft and cams, and the need for extra parts such as pins and keys. Further, the cams had to have matched pin holes or key ways in order to obtain a predetermined relationship between all the cams on a shaft. Still further, assembly was not facilitated since the pin holes or key ways in the cams and shafts had to be lined up in order to insert the pins or keys.
Also in the past, it was customary to put the detent mechanism external to rather than in the valve which required the mechanism to be large in size when detent forces were large.